Lubricating oil compositions comprising a heavy high saturates base oil

ABSTRACT

A lubricating oil composition comprising a heavy high saturates base oil is provided. Methods for using said lubricant composition for lubricating an engine, a gear box, and in general industrial lubricant applications, including as a bearing and circulating oil, are also provided.

The invention relates to a lubricating oil composition comprising a heavy high saturates base oil. Furthermore, the present invention relates to the use of said lubricant composition for lubricating an engine, a gear box, and use as a lubricant in general industrial lubricant applications, including as a bearing and circulating oil.

Heavy lubricants comprising high viscosity base oils are typically used in heavy load and/or high speed applications where base oils having a lower viscosity would not provide sufficient lubrication. Currently, many high viscosity base oils are derived from crude oils and are commercially manufactured using a solvent refining process.

High viscosity base oils derived from crude oils and manufactured using solvent extraction and solvent dewaxing processes typically contain sulphur, nitrogen and aromatic compounds, the presence of which can limit the performance of a finished lubricant containing such base oils. In contrast, high viscosity base oils manufactured via catalytic hydroprocessing contain predominantly saturated hydrocarbons and very little, if any, sulphur and nitrogen compounds.

However, there has been a desire in the art to assume that high viscosity base oils manufactured via catalytic hydroprocessing are unsuitable for finished lubricant and process oil applications, as in many cases such oils contain waxes that cause the oil appearance to be hazy and also because such oils lack intrinsic polarity necessary to adequately solubilize polar lubricant additives. Thus there is an overwhelming tendency to favour conventional, solvent refined base oils for high viscosity applications.

It has now surprisingly been found according to the present invention that heavy high saturates base oil derived from crude oil can be used in lubricant oil compositions to achieve several unexpected performance benefits.

Upon use of a lubricating oil composition according to the present invention in general lubricant applications, including as a bearing and circulating oil, in industrial gear oil, automotive gear oil, and in monograde heavy duty diesel engine oil, the formulation and the oil have better performance characteristics, such as a greater viscosity index, lower pour point, faster air release, and greater oxidation resistance than comparable conventional formulations and oils comprising a mineral bright stock.

In general, a heavy high saturates base oil suitable for use in the lubricating oil compositions of the present invention is a base oil comprising more than 80 wt % saturated hydrocarbons, and having a kinematic viscosity at 100° C. of at least 12 mm²/s, and a viscosity index of greater than 80. In addition, a heavy high saturates base oil suitable for use herein may be characterized by one or more of the features described herein below.

The heavy high saturates base oil comprises more than 80 wt % of saturated hydrocarbons, preferably more than 90 wt % of saturated hydrocarbons.

The kinematic viscosity at 100° C. according to ASTM D445 (VK 100) of the heavy high saturates base oil may typically be at least 12 mm²/s. Preferably, its VK 100 may be at least 15 mm²/s, more preferably at least 20 mm²/s, yet more preferably at least 25 mm²/s, and yet again more preferably at least 30 mm²/s.

The kinematic viscosity at 40° C. according to ASTM D445 (VK 40) of the heavy high saturates base oil may optionally be in the range of from 20 mm²/s to 500 mm²/s, preferably in the range of from 100 mm²/s to 460 mm²/s.

The viscosity index of the heavy high saturates base oil is preferably greater than 80, more preferably greater than 95, and preferably below 130.

The pour point of the heavy high saturates base oil according to ASTM D-5950 may be −5° C. or lower, preferably of −10° C. or lower, more preferably −15° C. or lower, and most preferably −20° C. or lower.

In general, a heavy high saturates base oil for use in the present invention may be prepared by any suitable refining process, for example by catalytic hydroprocessing. An example of a suitable refining process is described in WO 2011152680 A2, which is incorporated herein by reference.

The lubricating oil composition according to the present invention may comprise a heavy high saturates base oil as a minority or majority component. For example, the content of the heavy high saturates base oil in the lubricating oil composition may be 5% or greater, preferably of 10% or greater, more preferably 20% or greater, and most preferably 30% or greater.

In some embodiments, the lubricating oil composition may further comprise, in addition to a heavy high saturates base oil, an additional base oil, such as an API Group I base oil, an API Group II base oil, an API Group III base oil, an API Group IV base oil, an API Group V base oil, or a mixture thereof. By “API Group I”, “API Group II”, “API Group III”, “API Group IV”, and “API Group V” base oils, it is meant base oils according to the definitions of the American Petroleum Institute (API). These API categories are defined in API Publication 1509, 15th Edition, Appendix E, April 2002.

In some embodiments, the amount of additional base oil is in the range of from 5 to 95 wt %, or from 10 to 90 wt %, or from 15 to 60 wt %, based on the total weight of heavy high saturates base oil and additional base oil.

The amount of heavy high saturates base oil and the additional base oil present in a fully formulated lubricating oil composition will typically be the amount remaining to equal 100% after the remaining additives are accounted for. Generally, the heavy high saturates base oil and the additional base oil may make up the entirety of the lubricating oil composition, or preferably at least 75 wt. %, or at least 80 wt. %, or at least 90 wt. %, or at least 95 wt % or at least 98 wt %, or at least 99 wt % or at least 99.5 wt % or at least 99.99 wt % of the total lubricating oil composition.

The lubricating oil composition according to the present invention may further comprise one or more additives such as anti-oxidants, anti-wear additives, (preferably ashless) dispersants, detergents, extreme-pressure additives, friction modifiers, metal deactivators, corrosion inhibitors, demulsifiers, anti-foam agents, seal compatibility agents and additive diluent base oils, etc. Such additives will typically be present in low quantities.

As the person skilled in the art is familiar with the above and other additives, these are not further discussed here in detail. Specific examples of such additives are described in for example Kirk-Othmer Encyclopedia of Chemical Technology, third edition, volume 14, pages 477-526.

The lubricating oil composition may be used as a lubricant blendstock, or in any suitable lubricating application.

In a further aspect the present invention provides a method for making a lubricating oil composition by blending a heavy high saturates base oil with other base oils and lubricant performance additives. The lubricating oil composition may be formed by simple blending of its components as is known in the art.

In another aspect, the present invention provides the use of the lubricating oil composition for lubricating any surface that is in relative movement to another surface. For example, the lubricating oil compositions may be used to lubricate a surface of a rotating or sliding member in a vehicle or industrial machine. The lubricating oil compositions may also be useful to lubricate a surface in an engine (e.g., an internal combustion engine), a gear mechanism (e.g., in an industrial gear box or automotive gear box), a speed-change gearbox, a bearing, a hydraulic apparatus, compression machinery, etc.

As the person skilled in the art is familiar with the use of lubricating oil compositions for lubricating an engine, a gear box, etc., these are not further discussed here in detail.

One preferred application is the use of the lubricating oil composition according to the present invention as a lubricant in bearings and circulating oil applications. Bearing and circulating oils are used in a range of industrial systems from fairly heavy load applications such as steel making, where they are an essential lubricant for steel mill operation, to low load, high-speed applications such as textiles and other light manufacturing processes.

Bearing and circulating oils are generally the lubricant of choice in a centralized lubrication system. In this type of lubrication system, the oil is fed back through the return line into an oil reservoir for reuse (after passing through various points in the system requiring lubrication). In addition to providing lubrication, circulating oil lubrication systems perform a range of other functions, including stabilizing the temperature of the various lubrication points, removing and/or filtering out solid contamination or wear particles from points of contact, preventing rust and corrosion damage, and removing or reducing the effects of water. An effective bearing and circulating oil must be able to handle the challenging conditions just mentioned as well as potentially lubricate many different types of parts, such as bearings, gear sets, and pumps—all often lubricated by one centralized lubrication system. Like gear oils, most bearing and circulation system applications are lubricated by products that are of ISO 100 viscosity grade and higher.

The invention will now be further illustrated by the following non-limiting examples.

EXAMPLES

The kinematic viscosity at 100° C. and the percentage of saturated hydrocarbons (“saturates %”) of the base oils used in Samples A-H can be found in Table 1.

AC 2500 is a brightstock commercially available as Americas Core 2500 manufactured and sold by ExxonMobil Corporation. AC 2500 is a base oil derived from crude oils and manufactured using a solvent refining process, containing significant amounts of aromatic, sulphur, and nitrogen containing compounds.

SK 120BS is a Group II brightstock commercially available as SK 120BS manufactured and sold by SK Lubricants. SK 120BS is a heavy high saturates base oil derived from crude oils and manufactured using catalytic hydroprocessing, containing predominantly saturated hydrocarbons and very little, if any, sulphur and nitrogen compounds.

AP/E Core 600 is a Group I base oil commercially available as AP/E Core 600 manufactured and sold by ExxonMobil Corporation.

Shell 500N (Daesan) is a Group II base oil commercially available as Shell 500N (Daesan) manufactured and sold by Hyundai-Shell Base Oil Co.

Chevron 600R is a Group II base oil commercially available as Chevron 600R manufactured and sold by Chevron Corporation.

TABLE 1 Base Oil Properties AP/E Shell Test AC SK Core 500N Chevron Property Method 2500 120BS 600 (Daesan) 600R Kinematic ASTM 31.9 23.6 12.06 11.32 12.01 Viscosity D445 100° C., mm²/s Kinematic ASTM 493.3 318.5 112.1 95.07 101.2 Viscosity D445 40° C., mm²/s Viscosity ASTM 95 103 97 106 109 Index D2270 Saturates % IP 368 51.9 99.8 — 99.3 99.9 Pour Point ASTM −6 −42 −6 −18 −24 D5950

Preparation of Blend of Industrial Gear Oil Formulations

The Industrial Gear oil formulations were prepared by mixing the components as indicated in Table 2 and followed by stirring at 55° C. for 1 hour. Properties of these formulations can be found in Table 3.

TABLE 2 Industrial Gear Oil Formulations Sample A Components (Comparative) Sample B Viscosity Grade ISO 320 ISO 320 Concentrations in wt % AP/E Core 600 23.35 — AC 2500 73.95 25 SK 120BS — 72.3 Gear Oil Package¹ 2.5 2.5 Pour point depressant² 0.2 0.2 ¹Commercially available industrial gear oil additive package. ²Commercially available pour point depressant.

TABLE 3 Industrial Gear Oil Performance Data Sample A Sample Property Test Method (Comparative) B Kinematic Viscosity, 40° C., ASTM D445 319.8 299.7 mm²/s Kinematic Viscosity, 100° C., ASTM D445 24.14 24.63 mm²/s VI ASTM D2270 96 104 Air Release @ 75° C., min ASTM D3427 23 21 Viscosity Increase at 100 C., ASTM D2893 8.08 4.15 % Sample B shows performance advantages compared to Sample A including higher VI, lower pour point, faster air release, and better oxidation stability (indicated by lesser viscosity increase).

Preparation of Bearing and Circulating Oil Formulations

The Bearing and Circulating Oil Formulations as indicated in Table 4 were prepared by mixing the components used to prepare the formulations and followed by stirring at 55° C. for 1 hour. Properties of these formulations can be found in Table 5.

TABLE 4 Bearing and Circulating Oil Formulations Sample C Components (Comparative) Sample D Viscosity Grade ISO 320 ISO 320 Concentrations in wt % AP/E Core 600 23.87 — AC 2500 75.6 16 SK 120BS — 83.42 Bearing and circulating oil 0.43 0.43 additive package¹ Pour point depressant² 0.1 0.1 Demulsifier³ 300 ppm 300 ppm Anti-foam additive⁴ 200 ppm 200 ppm ¹Commercially available bearing and circulating oil additive package. ²Commercially available pour point depressant. ³Commercially available demulsifier. ⁴Commmercially available anti-foam additive.

TABLE 5 Bearing and Circulating Oil Performance Data Sample C Sample Property Test Method (Comparative) D Kinematic Viscosity, 40° C., ASTM D445 332.1 311.9 mm²/s Kinematic Viscosity, ASTM D445 24.58 24.37 100° C., mm²/s VI ASTM D2270 95 99 Pour Point, ° C. ASTM D5950 −9 −30 Air Release @ 75° C., ASTM D3427 17.11 14.38 min Air Release @ 50° C., ASTM D3427 83.21 56.64 min Oxidation Stability, ASTM D2272 550 1248 RPVOT (min) Sample D shows performance advantages compared to Sample C including higher VI, lower pour point, faster air release, and better oxidation stability.

Preparation of Monograde Heavy Duty Diesel Engine Oil Formulations

The Monograde Heavy Duty Diesel Engine Oil Formulations as indicated in Table 6 were prepared by mixing the components used to prepare the formulations and followed by stirring at 55° C. for 1 hour. Properties of these formulations can be found in Table 7.

TABLE 6 Monograde Heavy Duty Diesel Engine Oil Formulations Sample E Components (Comparative) Sample F Viscosity Grade SAE 50 SAE 50 Concentrations in wt % Shell 500N (Daesan) 65.3 59.3 AC 2500 27.99 — SK 120BS — 33.99 HDEO Additive Package¹ 6.41 6.41 Pour point depressant² 0.3 0.3 ¹Commercially available HDEO monograde engine oil additive package. ²Commercially available pour point depressant.

TABLE 7 HDEO Monograde Engine Oil Performance Sample E Sample Property Test Method (Comparative) F Kinematic Viscosity, 40° C., ASTM D445 175 169.8 mm²/s Kinematic Viscosity, 100° C., ASTM D445 17.03 17.06 mm²/s VI ASTM D2270 104 107 Pour Point, ° C. ASTM D5950 −33 −39 Pressure Differential CEC-L-085-99 101.2 98.8 Scanning Calorimetry, oxidation induction time (minutes) Sample E shows performance advantages compared to Sample F including higher VI, lower pour point, and better oxidation stability.

Preparation of Automotive Gear Oil Formulations

The Automotive Gear Oil Formulations as indicated in Table 8 were prepared by mixing the components used to prepare the formulations and followed by stirring at 55° C. for 1 hour. Properties of these formulations can be found in Table 9.

TABLE 8 Automotive Gear Oil Formulations Sample G Components (Comparative) Sample H Viscosity Grade SAE 85W-140 SAE 85W-140 Concentrations in wt % Chevron 600R 10.5 — AC 2500 85.6 44.8 SK 120BS — 51.3 Automotive Gear Oil Additive Package¹ 3.7 3.7 Pour point depressant² 0.2 0.2 ¹Commercially available automotive gear oil additive package. ²Commercially available pour point depressant.

TABLE 9 Automotive Gear Oil Performance Sample G Sample Property Test Method (Comparative) H Kinematic Viscosity, ASTM D445 343.9 326.3 40° C., mm²/s Kinematic Viscosity, ASTM D445 25.47 25.35 100° C., mm²/s VI ASTM D2270 97 100 Pour Point, ° C. ASTM D5950 −15 −33 Brookfield ASTM D2983 103000 32300 Viscosity, −12° C., cP DKA Oxidation CEC L-48-A-00, 198.3 98.9 Method B @ 150° C. (ASTM D7214) (Oxidation at FTIR) Sample H shows performance advantages compared to Sample G including higher VI, lower pour point, lower Brookfield viscosity, and better oxidation stability. 

1. A lubricating oil composition comprising a heavy high saturates base oil.
 2. A lubricating oil composition according to claim 1, wherein the heavy high saturates base oil comprises more than 80 wt % saturated hydrocarbons.
 3. A lubricating oil composition according to claim 1 or 2, wherein the heavy high saturates base oil has a viscosity index of greater than
 80. 4. A lubricating oil composition according to any one of claims 1 to 3, wherein the heavy high saturates base oil has a kinematic viscosity at 100° C. of at least 12 mm²/s.
 5. A lubricating oil composition according to any one of claims 1 to 4, wherein the pour point is −5° C. or lower.
 6. Use of lubricating oil composition according to any one of claims 1 to 5 for lubricating an engine, an industrial gear box, an automotive gear box, and use as a lubricant in general industrial lubricant applications including as a bearing and circulating oil. 